Energy Recovery Ventilator And Dehumidifier

ABSTRACT

An energy recovery ventilator system includes a belt partially located in each of a first chamber and a second chamber. First and second desiccant units are positioned on the belt. At least some of the first desiccant units are in the first chamber at a first relative humidity, causing air received in the first chamber to achieve a first air humidity. At least some of the second desiccant units are in the second chamber at a second relative humidity, the second relative humidity being caused by the air received in the first chamber. The second relative humidity is modified to the first relative humidity by air passing through the second chamber, the air achieving a second air humidity. A controller causes the belt to move second desiccant units from the second chamber to the first chamber when the first air humidity fails to comply with a specific air humidity.

FIELD OF THE INVENTION

The present invention relates generally to an energy recovery system,and, more particularly, to an energy recovery ventilator anddehumidifier having a desiccant in a saturated equilibrium state.

SUMMARY OF THE INVENTION

According to one aspect, an energy recovery ventilator system includes afirst chamber and a second chamber. A moving belt has a first portionpositioned in the first chamber and a second portion positioned in thesecond chamber. A plurality of desiccant units are positioned on themoving belt, the plurality of desiccant units including a plurality offirst desiccant units and a plurality of second desiccant units, each ofthe desiccant units being in a saturated stated. The first desiccantunits are located in the first chamber at a first relative humidity forcausing air received in the first chamber to achieve a first airhumidity. The second desiccant units are located in the second chamberat a second relative humidity, the second relative humidity being causedby the air received in the first chamber. The second desiccant units aremodified back to the first relative humidity by air passing through thesecond chamber, the air passing through the second chamber achieving asecond air humidity. A controller is communicatively coupled to themoving belt and is operable to cause movement of the moving belt.Specifically, the controller causes the moving belt to move at leastsome of the second desiccant units from the second chamber to the firstchamber when the first air humidity fails to comply with a predeterminedair humidity.

According to another aspect, a method for recovering energy in aventilator system is directed to receiving fresh air from an externalenvironment into a dehumidifier chamber. Moisture is adsorbed from thefresh air to a plurality of first desiccant units to lower the humidityof the fresh air, the first desiccant units being in a saturated stateat a first relative humidity. Dehumidified air is sent into a roomenvironment, and room air is received from the room environment into anenergy recovery chamber. Moisture is removed from the room air to aplurality of second desiccant units, the second desiccant units being ina saturated state at a second relative humidity. The removal of themoisture causes the saturated state at the second relative humidity ofthe second desiccant units to change to the saturated state at the firstrelative humidity. In response to determining that relative humidity offresh air is higher than a predetermined humidity, at least one of thefirst desiccant units from the dehumidifier chamber is replaced with acorresponding one of the second desiccant units from the energy recoverychamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may best be understood by reference to the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a diagrammatic of an energy recovery ventilator system,according to one embodiment.

FIG. 2 is a chart illustrating adsorbent capacities of Silica Gel.

FIG. 3 is an illustration of the energy recovery ventilator system in anenergy recovery ventilator (ERV) and regeneration mode.

FIG. 4 is an illustration of the energy recovery ventilator system in adehumidifier mode.

FIG. 5 is an illustration showing sensors of the energy recoveryventilator system

FIG. 6 is a perspective view of a heat exchanger and duct system,according to an alternative embodiment.

FIG. 7 is a side view illustration of the heat exchanger.

FIG. 8 is a perspective exploded view of the heat exchanger.

FIG. 9 is a top view illustration of a partial layer of the heatexchanger having a plurality of air-diverting deformations, according toone embodiment.

FIG. 10 is a top view illustration of a partial layer of the heatexchanger having an array of air-diverting deformations, according to analternative embodiment.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Although the invention will be described in connection with certainpreferred embodiments, it will be understood that the invention is notlimited to those particular embodiments. On the contrary, the inventionis intended to cover all alternatives, modifications, and equivalentarrangements as may be included within the spirit and scope of theinvention as defined by the appended claims.

Referring to FIG. 1, an energy recovery ventilator (“ERV”) system 100includes an air inlet 102 through which, typically, fresh air enters theERV system 100. The ERV system 100 is useful in stabilizing humidityyear-round, including during the winter and the summer, and has atheoretical efficiency near 100%. As explained in more detail inreference to FIGS. 3 and 4, the ERV system can be operated at least inan ERV mode and a dehumidifier mode. A first motor control damper 104(e.g., a fresh air damper) is positioned generally proximate to thefresh air inlet 102. The fresh air passes through a first filter 108into a dehumidifying chamber 110 in which a desiccant belt 112 islocated, in part. The desiccant belt 112 includes a plurality ofseparators 114, between which desiccant units 116 (e.g., silica gelpackets) are located.

In the dehumidifying chamber 110, the fresh air is modified to achieve adesired humidity. The modified fresh air exits the dehumidifying chamber110 at relative humidity through a first heat source 118, past a firstfan 120 (which drives the flow of air) and a second filter 122, into acounterflow heat exchanger 124 to achieve a desired temperature. Fromthe heat exchanger 124, the modified fresh air exits via an outlet duct126, typically, into a room that is being cooled.

On an exhaust path, room air enters an inlet duct 128 of the heatexchanger 124 and passes through a third filter 130, a second fan 132(which drives the flow of air), and a second heat source 134, into aregeneration chamber 136. The room air, as explained in more detailbelow, is useful for regenerating the desiccant units 116 on thedesiccant belt 112, which is movable between the dehumidifying chamber110 and the regeneration chamber 136.

A motor 137 is operated to move the desiccant belt 112 between the twochambers 110, 136. If the ERV system 100 is not in a dehumidifier mode(which is described in more detail below in reference to FIG. 3), theroom air exits the ERV system 100 via an air outlet 138. The secondmotor control damper 106 (which functions as a bypass damper) isoperable to divert the air flow between the desiccant belt 112, in thedehumidifying chamber 110, and a bypass duct 140. An anti-back flow flap142 is operated between an open position (as illustrated) and a closedposition (illustrated in FIG. 4) to control air flow towards the airoutlet 138.

Referring to FIG. 2, a chart illustrates adsorbent properties of variousdesiccants in relation to a Silica Gel material, which, in contrast toother materials, has a generally linear capacity versus relativehumidity in the range of 20-80%. For example, the Silica Gel can adsorb10 kilograms of water (per 100 kilograms of Silica Gel) at about 20%relative humidity, and about 30 kilograms of water (per 100 kilograms ofSilica Gel) at about 60% relative humidity. Thus, the adsorbent capacityof Silica Gel increases, generally linearly, with the relative humidityat a rate of about 1 kilogram of water for about 2% increase in relativehumidity.

For the ERV system 100 of the present application, a material exhibitingproperties similar to the Silica Gel is preferred because such amaterial provides good adsorbent capacity, adsorbing sufficient waterfrom the passing air, and because such a material can properly achieve adesired relative humidity based on the linear adsorbent capacityrelative to the relative humidity.

Referring to FIG. 3, the ERV system 100 is illustrated in the ERV modein which fresh air is regulated to a desired humidity, via thedehumidifying chamber 110, and a desired temperature, via the heatexchanger 124. Then, the regulated air is exhausted to a roomenvironment through the outlet duct 126. When passing through thedehumidifying chamber 110, the air passes through the desiccant units116 so that undesired air moisture is absorbed before the air exits tothe heat exchanger 124. The first control damper 104 is in an openposition, to allow exterior air to come in the ERV system 100, and thesecond control damper 106 is in a closed position to divert the air intothe dehumidifying chamber 110. The first fan 120 is operated to pull theair through the dehumidifying chamber 110, into the heat exchanger 124.

On the return path, air from the room environment enters the inlet duct128 and is pulled by the second fan 132 through the heat exchanger 124into the regeneration chamber 136. The second control damper 106 is inthe closed position to ensure that the air passes through theregeneration chamber 136, and does not flow through the bypass duct 140.From the regeneration chamber 136, the air exits through the air outlet138 to the exterior environment.

In the regeneration chamber 136, the desiccant belt 112 includesdesiccant units 116 that require regeneration. After adsorbing moisturefrom the air in the dehumidifying chamber 110, the desiccant units 116reach a state in which they become saturated at a higher humidity leveland, as such, the desiccant units 116 are no longer removing the desiredhumidity from the air. When this state is reached, the desiccant belt112 is rotated to move the desiccant units 116 from the dehumidifyingchamber 110 to the regeneration chamber 136. In the regeneration chamber136, heated and dry air that is expelled from the room environment isutilized to regenerate (or dry) the desiccant units 116. In other words,the relative humidity of the desiccant units 116 is reduced in theregeneration chamber 136. Moisture from the desiccant units 116 (whichare now in the regeneration chamber 136) is removed by the passingheated and dry air, which would otherwise be expelled directly towardsthe air outlet 138 (to the outside, external, environment).

The desiccant belt 112 is rotated to maintain the desiccant units 116 ina saturated equilibrium state to maintain a specific relative humidity.The desiccant belt 112 includes a sufficient volume of desiccant units116 to achieve the desired relative humidity. According to oneembodiment, the volume of desiccant units 116 is high enough to preventcontinuous movement of the desiccant belt 112. In other words, thevolume of desiccant units 116 is high enough to permit a stationary timeperiod of the desiccant 112, before rejuvenation of the desiccant units116 is necessary.

Referring to FIG. 4, the ERV system 100 is illustrated in thedehumidifier mode, in which air from the room environment isdehumidified in the dehumidifier chamber 110. In the dehumidifier mode,the first control damper 104 is in the closed position to prevent freshair from entering the ERV system 100, and the anti-back flow flap 142 isalso in the closed position to prevent air expelled from the roomenvironment to exit the ERV system 100 via the air outlet 138. Thesecond control damper 106 is in the open position to allow the airexpelled from the room environment to bypass the regeneration chamber136 via the bypass duct 140. From the bypass duct 140, the air isrecirculated to the dehumidifier chamber 110 by moving the secondcontrol damper 106 in the open position. In the dehumidifier chamber110, air from the room environment is regulated to the desired humidityand, then, to the desired temperature in the heat exchanger 124, afterwhich it is passed back toward the room environment.

The second heat source 134 can be a thermal mass that is used to capturethe heat of condensation transferred to the incoming air stream in theheat exchanger 124. After a sufficient amount of heat is captured by thethermal mass, the ERV system 100 switches temporarily to the ERV mode toregenerate the desiccant units 116. In another embodiment, the heatsource 134 can be a condenser coil located in the high pressure/hot areaof an associated air conditioner unit for using waste heat from the airconditioner unit to regenerate the desiccant when the ERV system 100 isin the dehumidifier mode. Thus, the dehumidifier mode recirculates airto/from the room environment such that the only actions are to regulatethe air temperature and humidity in the dehumidifying chamber 110. Incomparison, the ERV mode circulates air to/from the external environmentsuch that the air temperature and humidity is regulated in thedehumidifying chamber 110 and desiccant units 116 are regenerated in theregeneration chamber 136.

Referring to FIG. 5, the ERV system 100 is illustrated with a pluralityof sensors, including humidity and temperature (HT) sensors 144 a-144 d,a position (P) sensor 146, and a temperature (T) sensor 148. Thehumidity and temperature sensors 144 a-144 d include a first sensor 144a near the dehumidifier chamber 110, a second sensor 144 b in theregeneration chamber 136, a third sensor 144 c in the outlet duct 126,and a fourth sensor 144 d in the inlet duct 128.

The sensors are communicatively coupled to a central processing unit(“CPU”) 150, which has an optional antenna 152 for receiving/sendingcommunications. This communication channel can be used, for example, forreporting operational parameters, maintenance status, and operatingsystem upgrades. A power supply 154 provides the required electricalpower to operate the ERV system 100. The CPU 150 causes the desiccantbelt 112 to move intermittently when a determination is made that theair in the ERV system 100 has degraded to an undesired temperatureand/or humidity. The humidity and temperature (HT) sensors 144 a-144 dprovide input to the CPU 150 to determine the amount of energy that hasto be recovered. Accordingly, when the energy being recovered is lowerthan a predetermined energy value, the desiccant belt 112 is moved.

The position sensor 146 senses the position of the desiccant belt 112 toidentify movement of the separators 114, as they move between thedehumidifier chamber 110 and the regeneration chamber 136. Twoseparators of the separators 114, such as a first separator 114 a and asecond separator 114 b, are always positioned in an area between thedehumidifier chamber 110 and the regeneration chamber 136 to seal thetwo chambers from each other and, consequently, to preventcross-contamination between air flowing through respective chambers.

In reference to FIGS. 1-5, the ERV system 100 has been described as bothan ERV system and a dehumidifier typically as used during the warm andhumid months of the year (e.g., summer season). However, the ERV system100 can also be used during the cold and dry months of the year (e.g.,winter seasons), but in reverse. For example, reversing the process,moist desiccant units 116 that require regeneration are now in thedehumidifying chamber 110 and dry regenerated desiccant units 116 arenow in the regeneration chamber 136. As such, cold dry air from theexternal environment passes through the moist desiccant units 116positioned in the dehumidifying chamber 110, and is humidified in theprocess. In the return path, hot humid air from the room environmentpasses through the dry desiccant units 116 in the regeneration chamber136, filling the dry desiccant units 116 with moisture to be used (afterthe desiccant belt 112 is rotated) in the humidifying chamber 136.

Referring to FIG. 6, a counterflow heat exchanger 600 has a plurality oflayers 602 through which air flows between an external environment and aroom environment. Fresh air is directed to the heat exchanger 600through a first inlet portion 604, from the external environment, andexits through a first outlet portion 606, to the room environment. Roomair is directed to the heat exchanger 600 through a second inlet portion608 from the room environment, and exits through a second outlet portion610.

Referring to FIG. 7, the heat exchanger 600 further includes a pluralityof plates 612 separated by a plurality of separator segments 614 (alsoreferred to as tape segments). The plates 612 can be made from anydesirable material, such as foam tape (e.g., open foam tape) or moldedtape, and can have a relatively small thickness, such as a 10thousandths of an inch thickness. The separator segments 614 are, ingeneral, attached around the periphery of the plates 612 or in aninternal area between the plates 612. The heat exchanger 600 furtherincludes a plurality of deformations 616 that are formed on the surfaceof the plates 612.

Referring to FIG. 8, some separator segments 614 a, 614 b are orientedacross respective ones of the plates 612 to direct air flow in aparticular pattern. The deformations 616 are positioned on each layer602 in a desired pattern to create a respective air flow within the heatexchanger 600. The orientation of the deformations 616 is dependent onthe direction of the air flow. For example, the orientation ofdeformations 616 on a first layer 602 a, through which air may flow fromthe external environment to the room environment, can be directlyopposite to the orientation of the deformations 616 on a second layer602 b, through which air may flow from the room environment to theexternal environment.

The deformations 616 are positioned such that turbulent air flow isachieved in the heat exchanger 600. The deformations 616 can includeprotruding deformations and/or embossing deformations. Protrudingdeformations are deformations raised above a thickness plane of theplate 602 (as illustrated in FIG. 8), and embossing deformations aredeformations punched below the thickness plane of the pate 602 (notshown). Although the deformations 616 are shown to have a triangularshape, the deformations 616 can have other shapes.

Referring to FIGS. 9 and 10, the deformations 616 can be positioned andoriented in various ways. For example, as illustrated in FIG. 9, only asmall number of deformations 616 can be positioned on the plate 612,each of the deformations 616 being oriented in the same direction on theplate 612. In another example, illustrated in FIG. 10, a large number ofdeformations 616 can be positioned on the plate 612, each of thedeformations 616 having a different orientation than at least some ofthe other deformations 616.

The heat exchanger 600 may be considered to be a disposable heatexchanger because it consists primarily of elements (e.g., plates 612and separator segments 614) that are relatively inexpensive and easy tomanufacture. For example, the cost of one embodiment of the disclosedheat exchanger 600 may be about $50, in contrast to some present heatexchanger that may cost thousands of dollars. Another advantageousaspect of having the separator segments 114 is that they act as amuffler to reduce noise entering the building.

While particular embodiments and applications of the present inventionhave been illustrated and described, it is to be understood that theinvention is not limited to the precise construction and compositionsdisclosed herein and that various modifications, changes, and variationsmay be apparent from the foregoing descriptions without departing fromthe spirit and scope of the invention as defined in the appended claims.

1. An energy recovery ventilator system comprising: a first chamber anda second chamber; a moving belt having a first portion positioned in thefirst chamber and a second portion positioned in the second chamber; aplurality of desiccant units positioned on the moving belt, thedesiccant units including a plurality of first desiccant units and aplurality of second desiccant units, each of the desiccant units beingin a saturated stated, the first desiccant units being located in thefirst chamber at a first relative humidity and causing air received inthe first chamber to achieve a first air humidity, and the seconddesiccant units being located in the second chamber at a second relativehumidity, the second relative humidity being caused by the air receivedin the first chamber, the second desiccant units being modified back tothe first relative humidity by air passing through the second chamber,the air passing through the second chamber achieving a second airhumidity; and a controller communicatively coupled to the moving beltand operable to cause movement of the moving belt, the controllercausing the moving belt to move at least some of the second desiccantunits from the second chamber to the first chamber when the first airhumidity fails to comply with a predetermined air humidity.
 2. Theenergy recovery ventilator system of claim 1, wherein a gap is formedalong an adjacent boundary between the first chamber and the secondchamber, the moving belt including a plurality of separators positionedat predetermined intervals on the moving belt, at least one of theseparators being positioned in the gap to seal the first chamber fromthe second chamber and prevent cross-contamination between air in thefirst chamber and air in the second chamber.
 3. The energy recoveryventilator system of claim 1, wherein the plurality of desiccant unitsare packets of silica gel.
 4. The energy recovery ventilator system ofclaim 1, wherein the first chamber operates in a dehumidifier mode inwhich moisture is removed from the air in the first chamber by passingthrough the first desiccant units, the second chamber operating in anenergy recovery mode in which moisture is added to the air passingthrough the second chamber by passing through the second desiccantunits.
 5. The energy recovery ventilator system of claim 1, wherein thefirst chamber operates in a dehumidifier mode during a first time periodand in a reverse mode during a second time period.
 6. The energyrecovery ventilator system of claim 1, wherein, in an energy recoverymode, the air passing through the second chamber is expelled to theexternal environment.
 7. The energy ventilator system of claim 1,further comprising a plurality of sensors, including humidity andtemperature sensors, a position sensor, and a temperature sensor, afirst one of the humidity and temperature sensors being positioned nearthe first chamber; a second one of the humidity and temperature sensorsbeing positioned near the second chamber; a third one of the humidityand temperature sensors being positioned near an outlet duct of a heatexchanger that is located adjacent to the first chamber and the secondchamber; and a fourth one of the humidity and temperature sensors beingpositioned near an inlet duct of the heat exchanger; wherein theposition sensor is located in the second chamber near the moving beltand the temperature sensor is located in the second chamber.
 8. Theenergy ventilator system of claim 1, wherein the controller is coupledto a position sensor, the controller determining whether a gap betweenthe first chamber and the second chamber is properly sealed based onpositioning input received from a position sensor located near themoving belt.
 9. The energy ventilator system of claim 1, furthercomprising a heat exchanger including a plurality of layers, each of thelayers having two plates separated by a plurality of separator segments.10. The energy ventilator system of claim 9, wherein the plurality ofseparator segments include one or more foam tape segments or molded tapesegments.
 11. The energy ventilator system of claim 9, wherein at leastone of the plates is an aluminum plate having at least one deformationformed on a plate surface for deflecting flow of air in the heatexchanger to create a turbulent air flow.
 12. The energy ventilatorsystem of claim 11, wherein the at least one deformation is selectedfrom a group consisting of a protrusion deformation and an embossmentdeformation.
 13. The energy ventilator system of claim 9, wherein atleast one of the plates has an array of deformations formed on a platesurface, the array causing a turbulent air flow in the heat exchanger.14. A method for recovering energy in a ventilator system, the methodcomprising: receiving fresh air from an external environment into adehumidifier chamber; adsorbing moisture from the fresh air to aplurality of first desiccant units to lower the humidity of the freshair, the first desiccant units being in a saturated state at a firstrelative humidity; sending dehumidified air into a room environment;receiving room air from the room environment into an energy recoverychamber; removing moisture from the room air to a plurality of seconddesiccant units, the second desiccant units being in a saturated stateat a second relative humidity, the removing of the moisture causing thesaturated state at the second relative humidity of the second desiccantunits to change to the saturated state at the first relative humidity;and in response to determining that relative humidity of fresh air ishigher than a predetermined humidity, replacing at least one of thefirst desiccant units from the dehumidifier chamber with a correspondingone of the second desiccant units from the energy recovery chamber. 15.The method of claim 14, further comprising expelling the room air to theexternal environment after passing through the energy recovery chamber.16. The method of claim 14, further comprising sealing gaps formedbetween the dehumidifier chamber and the energy recovery chamber withseparators formed in a rotating belt.
 17. The method of claim 14,further comprising passing the dehumidified air through layers of a heatexchanger, the layers being formed by two adjacent plates separated bytape segments.
 18. The method of claim 17, further comprising creating aturbulent air flow by passing the dehumidified air passed an array ofdeformations formed on a surface of at least one of the plates.